In 1937, Shanghai was on the eve of the fall. The "Shiguang Photo Studio" in the French Concession became a refuge and battlefield for eleven men. They use light and shadow as cover to conduct espionage. Zhou Zhennan and Yao Chen, one is the commander and the other is the executor, each other is the only light in the dark night. When the shadow of the traitor loomed, and when trust trembled under the gun, they used their lives to write eleven love letters that could never be delivered. During the six years of war, some people slept before dawn, while others walked alone to the end of their lives carrying their memories.
